UN/NA Number Reference
DOT Class 2.1 Flammable Gas placard

UN 1959: 1,1-Difluoroethylene

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1959 is assigned the proper shipping name 1,1-Difluoroethylene in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 2.1 Flammable Gas material. Required label(s): 2.1.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 116)

Hazards: May polymerize explosively when heated or involved in fire. Extremely flammable. BLEVE risk.

Fire: Fight fire from maximum distance. Do not extinguish unless flow stopped. Cool containers with water.

Spill: Eliminate all ignition sources. Stop leak if safe.

Chemical and Physical Properties

1,1-Difluoroethylene (or vinylidene fluoride) is a colorless gas which is flammable in the ranges of 5.5 to 21%. It is toxic by inhalation and contact. It is slightly soluble in water and soluble in alcohol and ether. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket.

CAS Number: 75-38-7
Molecular Formula: C2H2F2
Molecular Weight: 64.03 g/mol
Color / Form: Colorless gas
Odor: Nearly odorless
Boiling Point: -123 F
Melting Point: -227 °F (NTP, 1992)
Flash Point: Flammable gas
Autoignition: 1184 °F (NTP, 1992)
Specific Gravity: 0.617 (floats on water)
Vapor Pressure: 21584 mmHg at 50 F
Vapor Density: 2.2 (heavier than air)
Water Solubility: 0.018 g/100 g at 77 F and 760 mmHg
Log P: log Kow = 1.24

Regulatory Data

OSHA PEL
none
NIOSH REL
TWA 1 ppm C 5 ppm [use 1910.1017]
IDLH
N

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Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.